Saint Hilary of Poitiers was a prominent Christian bishop and theologian in the 4th century. Born around 315 AD in Poitiers, France, he is known for his strong defense of the Christian faith against Arianism, a belief that denied the divinity of Christ. Hilary became the Bishop of Poitiers and was later exiled for his opposition to Arianism, during which he wrote several influential works, including his famous treatise, On the Trinity. He is often referred to as the "Athanasius of the West" due to his theological contributions and commitment to orthodoxy. Saint Hilary was canonized as a saint and is celebrated on January 13. His feast day is recognized in the Roman Catholic Church and the Eastern Orthodox Church, highlighting his enduring legacy in Christian history.